I need help understanding why GParted is still showing space used on a hard drive.

I am moving files from a hard drive that I normally have connected to NAS device. The hard drive is connected to my desktop and is not the primary drive. I have successfully moved the files to a secondary location. However, there appear to be files that are not showing up.

When I run GParted it shows that 14.60 GiB are still being used. Files do not show in the GUI with hidden on. Additionally I have used terminal including the 'ls -a' command with no results.